Mulching
Why soil should be kept covered
Wherever possible, nature covers the ground with a layer of protective plants or, in forests, with leaves, needles and brushwood. Mulching can achieve a similar effect in private gardens. A dense layer of organic material has a balancing effect in extreme weather conditions – just one of its many advantages.
The advantages of mulching
Mulching with organic materials is an ideal way to protect and nourish the soil. Even on the most infertile soils, it can create flourishing and productive gardens – in kitchen gardens as well as in perennial beds and ornamental shrubbery.
protective function
The mulch layer protects cultivated soil from physical impacts. For example, it protects against extreme weather conditions, strong winds, damaging drying out, cracking and crusting, as well as soil erosion – the dreaded erosion.
At the same time, the soil surface is protected from excessive heating by solar radiation, as well as from silting and washing away as a result of heavy rainfall.
Mulched soils not only show a balanced temperature throughout the day, but also fewer frost days and lower frost depths than comparable areas. This gives soil organisms a longer period of activity. This results in better conversion processes in the soil, humus formation and stabilisation of soil fertility.
Because there is no tillage in a mulched garden, the sensitive fine root system of cultivated plants is not destroyed by mechanical damage. The mulch cover also helps to save water by reducing evaporation.
nutrient blanket
Mulch layers are an excellent nutrient cover for all soil organisms that interact with plants. The extra layer perfectly meets their needs for food, water, warmth and air. The result is intensified soil activity – a prerequisite for the desired ideal condition: “& gt; soil fertility” (http://web.oscorna.de/gartenwissen/mulchen/#bodengare).
Even compost cannot achieve the same soil performance as mulching with fresh, living materials. Permanent greening and mulching in fruit growing have even found a way to counteract the dreaded fruit tree fatigue.
Weed reduction
The mulch layer largely suppresses seed weeds in particular and therefore significantly reduces the amount of work required for crop maintenance. Weed-related competition for water and nutrients is also significantly reduced.
Weed growth depends on the mulch cover. Without mulch, weeds cover 100 per cent of the soil. Even a 3 cm layer of mulch reduces weed growth to just 22 per cent. A 5 cm layer of mulch reduces weed growth to up to 10 per cent and a 7 cm layer to up to 8 per cent.
Mulch materials
A mulch cover can be made up of a wide variety of components. Apply as thick a layer as possible. The more alive the garden soil is, the faster the mulch cover will decompose until only a thin layer of humus remains.
Mulch materials
Compost – green waste – grass clippings – leaves – weeds – bark products – only the finest
| Nettles: | Excellent mulch material that can be cut repeatedly from spring to summer. Contributes to improving humus quality. |
| Comfrey leaves: | Special material containing potassium. Particularly good for tomatoes. |
| Mixed herbs: | Thanks to their valuable ingredients, they have a generally beneficial effect on the soil and plants. |
| Tomato leaves: | Placed around the tomatoes. Tomatoes grow particularly well with them. Tomato leaves and side shoots placed between cabbage plants help to repel cabbage white butterflies. |
| Coffee grounds: | Incidentally, these are particularly suitable as ground cover for bog plants such as azaleas, rhododendrons, ericas, etc. |
Other mulch materials
| Bark mulch: | Often contains tannic acid and is therefore particularly suitable for bog plants such as rhododendrons, heather, blueberries, etc. Decayed bark mulch, known as bark humus, is much more suitable. |
| Semi-mature compost: | Has a very stimulating effect on soil life in the humus layer. The compost layer is covered with a little grass or other mulch materials to keep the compost warm and moist. This supports further decomposition into humus. |
| Leaves: | Should be laid as a natural ground cover in autumn, especially under shrubs and hedges. |
| Grass clippings: | Should not be mulched thicker than 1-2 cm, otherwise they will form a dense layer during decomposition. This impairs the important air-gas exchange in the soil. Allow the grass to wilt slightly beforehand. |
| Green manure: | These are living plants such as mustard seeds, lupins and clover, which first grow on this bed as catch crops and are later mowed. They then remain on the ground as a layer of mulch. |
| Ground cover: | These are low-growing, perennial plants that grow so densely together that weeds are suppressed. The soil remains moist for longer and is protected from the effects of the weather. |
Mulching and fertilising
When mulching with materials rich in raw fibre (bark mulch, wood chips, etc.), we strongly recommend compensatory fertilisation.
As this mulch material with a high wood content decomposes, nutrients are bound in the soil and removed from the plants as food. The resulting deficit leads to deficiency symptoms (light discolouration and stunted growth).
For your shopping list
Application of Oscorna Soil Activator
| Application | Oscorna Soil Activator | Oscorna Tree, Shrub and Hedge Fertiliser |
|---|---|---|
| Application rate: | 200 g/m² | 100 g/m² |
| Main application period: | January to December | January to December |
| Package size and coverage: |
3 kg for 15 m² 10 kg for 50 m² 25 kg for 125 m² |
5 kg for 50 m² 10.5 kg for 105 m² |
Our tip: Ideally, fertilise and improve the soil before mulching.
It is also possible to add Oscorna products to the mulch material on top if these are then raked in with a leaf rake and thoroughly washed in with a garden hose.
Advice on mulching practices
To ensure proper, fully effective mulching, the following should be observed:
Ensure that the cultivated soil is completely covered throughout the year.
- Short-cut or shredded mulch material is easier to spread, the rotting process is more manageable and progresses quickly. This is especially true when Oscorna compost accelerator is added.
- In practice, spreading a layer of Oscorna compost accelerator on top of the mulch has proven to be an effective way of breaking down mulch quickly. This immediately stimulates such vigorous activity among the soil organisms that you can see the mulch breaking down within a short space of time.
- Before applying the topsoil layer, the surface of the soil should be roughened with a hoe or garden fork.
- Leave the mulched areas completely undisturbed: the mulch layer provides both protection and nutrients. In general, the organic materials in the mulch layer provide the plant with all the nutrients and active ingredients (in combination with Oscorna products) it needs to thrive. The processes of substance replenishment, in line with the growth cycle, are in balance, and any external influence disrupts the structure and decomposition mechanisms.
- Simply pull out weeds and leave them on the mulch cover.
Tailored to the soil type
Paying attention to soil conditions will yield better results when mulching
Light, sandy soils
Sandy soils are particularly suitable for mulching, as the results are visible after only a short time. Even with thicker layers of mulch, there is hardly any undesirable rotting.
If the soil is covered systematically, digging and other heavy soil cultivation is unnecessary. Combining Oscorna products with mulching can significantly increase the binding power of these light soils. It is always important to ensure even coverage. This leads to active soil life, including soil nutrition.
This is how tired soil can be revitalised more quickly:
- Spread approximately 150 g/m² of Oscorna Soil Activator on the topsoil, roughen it up with a hoe or garden fork and cover it with a layer of mulch approximately 2 cm thick.
- Then add some Oscorna Compost Accelerator and Oscorna Animalin.
- When adding to the mulch layer next time, first apply a thin layer of Oscorna Soil Activator and then add a layer of compost approximately 2 cm thick. Follow this with a layer of mulch approximately 2 cm thick. Leave everything to rest.
Heavy, clayey soils
With clay soils, mulching with organic materials is somewhat more complicated: on the one hand, soil aeration and water retention are unfavourable, and on the other hand, the late warming in spring delays the cultivation of the garden.
Mulching heavy soils therefore requires a little more effort and understanding – but this pays off in better results and higher yields.
How it works
For those who want to know exactly
This happens during mulching
As soon as the mulch is spread, the first decomposition processes begin.
They mainly take place in the contact zone between the soil and the mulch. Especially in the warm half of the year, a wide variety of microbes work intensively, especially fungi.
The conversion of nutrient-rich organic matter only occurs through contact with microbes and minerals. Cavities form, allowing for generous gas exchange. This makes carbon dioxide, for example, directly available for fertilisation, which the crops absorb through the stomata on the undersides of their leaves.
Although the visible surface is most exposed to sun, wind and rain, it initially remains seemingly unchanged. Only the finer particles are shifted to lower layers. This means that the protective function remains intact for a long time.
division of labour
The processing of organic matter by microorganisms takes place in so-called “working groups”. Each species is limited to a specific part of the decomposition process. The whole process is therefore not a random dissolution of structures, but takes place in a meaningful order.
The composition of the “recycling society” is determined by the availability of material. If our cultivated soils are rich in organic materials and, above all, diverse, we can also expect microbial activity that is rich in species and individuals.
Ideal soil condition
During the decomposition process, the number of microorganisms increases and colonies form with enormous cell proliferation. We refer to this as microbial soil decomposition or cell decomposition.
This soil structure is transient, as it consists of microbial bodies that die after the carbon compounds have been decomposed. Body substances and residues from the activity of microorganisms stick to soil particles and form the now visible soil crumbs. The upper layer of the topsoil becomes coarse-pored and permeable to air for active microbial activity.